Fat-based dibasic acids

Aside from “dimer acids” (E.C. Leonard’s paper), the best known fat-based dibasic acids consist of eight product types of which only four are commercially important. These are described in detail in this paper: (a.) Azelaic acid produced from oleic acid by either chrome oxidation or ozonolysis of oleic acid also, “brassylic” acid from mixed 55% erucic-containing crambe oil fatty acids. (b). Sebacic acid from castor oil or possibly dodecanedioic acid from lesquerolic acid by caustic fusion. (c) C-21 Dibasic acid by Diels Alder reaction between isomerized TOFA and acrylic acid. (d.) C-19 Dibasic acids (carboxystearic acids) from oleic acid by carboxylation. (e.) Mixed C-11/C-12 Dibasic acids by several routes. Both the alkali cleavage and gentle nitric acid oxidations of certain hydroxy fatty acids (e.g., 12-hydroxystearic acid from hydrogenation of ricinoleic acid, etc.) can be used to afford mixed C-11/C-12 dibasic acids. (f.) Dibasic acid mixtures by nitric acid oxidations. Depending upon conditions, both saturated and unsaturated fatty acids are oxidized to a heterogeneous mixture of mono- and dibasic acids by oxidation with nitric acid.